connect and create mysql database with php

this is a simple tutorial of how to connect and create mysql database with php.

it's a very good tutorial for beginners.

Create a Connection to a MySQL Database

Before you can access data in a database, you must create a connection to the database.
In PHP, this is done with the mysql_connect() function.

Syntax

mysql_connect(servername,username,password);

Example

In the following example we store the connection in a variable ($con) for later use in the script. The "die" part will be executed if the connection fails:

<?php
$con = mysql_connect("localhost","hassan","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// some code
?> 

Closing a Connection

The connection will be closed automatically when the script ends. To close the connection before, use the mysql_close() function:

<?php
$con = mysql_connect("localhost","hassan","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// some code

mysql_close($con);
?> 

Create a Database

The CREATE DATABASE statement is used to create a database in MySQL.

Syntax

CREATE DATABASE database_name

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example creates a database called "my_db":

<?php
$con = mysql_connect("localhost","hassan","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

if (mysql_query("CREATE DATABASE my_db",$con))
  {
  echo "Database created";
  }
else
  {
  echo "Error creating database: " . mysql_error();
  }

mysql_close($con);
?> 

Create a Table

The CREATE TABLE statement is used to create a table in MySQL.

Syntax

CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
column_name3 data_type,
....
) 

We must add the CREATE TABLE statement to the mysql_query() function to execute the command.

Example

The following example creates a table named "Persons", with three columns. The column names will be "FirstName", "LastName" and "Age":

<?php
$con = mysql_connect("localhost","hassan","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// Create database
if (mysql_query("CREATE DATABASE my_db",$con))
  {
  echo "Database created";
  }
else
  {
  echo "Error creating database: " . mysql_error();
  }

// Create table
mysql_select_db("my_db", $con);
$sql = "CREATE TABLE Persons
(
FirstName varchar(15),
LastName varchar(15),
Age int
)";

// Execute query
mysql_query($sql,$con);

mysql_close($con);
?> 

Important: A database must be selected before a table can be created. The database is selected with the mysql_select_db() function.
Note: When you create a database field of type varchar, you must specify the maximum length of the field, e.g. varchar(15).

Primary Keys and Auto Increment Fields

Each table should have a primary key field.
A primary key is used to uniquely identify the rows in a table. Each primary key value must be unique within the table. Furthermore, the primary key field cannot be null because the database engine requires a value to locate the record.
The following example sets the personID field as the primary key field. The primary key field is often an ID number, and is often used with the AUTO_INCREMENT setting. AUTO_INCREMENT automatically increases the value of the field by 1 each time a new record is added. To ensure that the primary key field cannot be null, we must add the NOT NULL setting to the field.

Example

$sql = "CREATE TABLE Persons 
(
personID int NOT NULL AUTO_INCREMENT,
PRIMARY KEY(personID),
FirstName varchar(15),
LastName varchar(15),
Age int
)";

mysql_query($sql,$con);